The present invention relates to a pivotal supporting structure for pivotally supporting a fallboard of a keyboard musical instrument in such a manner that the fallboard is openable and closable relative to the body of the musical instrument.
There have heretofore been known keyboard musical instruments where a fallboard (keyboard fallboard) is pivotally supported relative to the body of the musical instrument with a damper function secured for braking opening/closing movement of the fallboard. In a keyboard musical instrument disclosed in Japanese Patent No. 3849313, the fallboard pivotally mounted on a back lid of the keyboard is pivotally supported on a damper device (damper mechanism section) that is provided on the body of the musical instrument (or instrument body) and that has viscous resistance. In order to absorb misalignment between the pivot axis of the damper device and the pivot axis of the fallboard, a connection member and an absorbing member are interposed between the damper device and the fallboard.
In the pivotal supporting structure disclosed in the above-identified patent literature, however, the fallboard is pivotable relative to the keyboard back lid, and absolutely, the pivot center is a mechanism, such as a hinge, connecting the fallboard and the keyboard back lid for pivotal movement relative to each other. Further, the pivotal supporting structure disclosed in the above-identified patent literature is constructed so that axial misalignment between the pivot axis of the damper device and the fallboard is absorbed by axial misalignment adjusting members comprising the connection member and the absorbing member.
For that purpose, not only a pivotal supporting mechanism, such as the hinge, but also the misalignment adjusting members are essential. Further, because the pivot center of the fallboard does not necessarily coincide with the pivot center of the damper device, there is a likelihood that the damper function will not be exerted uniformly during the entire opening and closing strokes.
If one wants to mount the fallboard on the instrument body in such a manner that the fallboard pivots accurately about the pivot center of the damper device, then a construction corresponding to such a form of mounting has to be considered, which would make it difficult to realize easy mounting of the fallboard.